

<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  <title>Connecting to your Database &mdash; CodeIgniter 3.1.5 documentation</title>
  

  
  
    <link rel="shortcut icon" href="../_static/ci-icon.ico"/>
  

  
  <link href='https://fonts.googleapis.com/css?family=Lato:400,700,400italic,700italic|Roboto+Slab:400,700|Inconsolata:400,700&subset=latin,cyrillic' rel='stylesheet' type='text/css'>

  
  
    

  

  
  
    <link rel="stylesheet" href="../_static/css/citheme.css" type="text/css" />
  

  
    <link rel="top" title="CodeIgniter 3.1.5 documentation" href="../index.html"/>
        <link rel="up" title="Database Reference" href="index.html"/>
        <link rel="next" title="Queries" href="queries.html"/>
        <link rel="prev" title="Database Configuration" href="configuration.html"/> 

  
  <script src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js"></script>

</head>

<body class="wy-body-for-nav" role="document">

  <div id="nav">
  <div id="nav_inner">
    
    
    
      <div id="pulldown-menu" class="ciNav">
        <ul>
<li class="toctree-l1"><a class="reference internal" href="../general/welcome.html">Welcome to CodeIgniter</a><ul class="simple">
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer&#8217;s Certificate of Origin 1.1</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../general/index.html">General Topics</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../general/urls.html">CodeIgniter URLs</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/controllers.html">Controllers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/reserved_names.html">Reserved Names</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/views.html">Views</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/models.html">Models</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/helpers.html">Helpers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/libraries.html">Using CodeIgniter Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/creating_libraries.html">Creating Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/drivers.html">Using CodeIgniter Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/creating_drivers.html">Creating Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/core_classes.html">Creating Core System Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/ancillary_classes.html">Creating Ancillary Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/hooks.html">Hooks - Extending the Framework Core</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/autoloader.html">Auto-loading Resources</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/common_functions.html">Common Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/compatibility_functions.html">Compatibility Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/routing.html">URI Routing</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/errors.html">Error Handling</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/caching.html">Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/profiling.html">Profiling Your Application</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/cli.html">Running via the CLI</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/managing_apps.html">Managing your Applications</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/environments.html">Handling Multiple Environments</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/alternative_php.html">Alternate PHP Syntax for View Files</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/security.html">Security</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/styleguide.html">PHP Style Guide</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../libraries/index.html">Libraries</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../libraries/benchmark.html">Benchmarking Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/caching.html">Caching Driver</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/calendar.html">Calendaring Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/cart.html">Shopping Cart Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/config.html">Config Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/email.html">Email Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encrypt.html">Encrypt Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encryption.html">Encryption Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/file_uploading.html">File Uploading Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/form_validation.html">Form Validation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/ftp.html">FTP Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/image_lib.html">Image Manipulation Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/input.html">Input Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/javascript.html">Javascript Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/language.html">Language Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/loader.html">Loader Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/migration.html">Migrations Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/output.html">Output Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/pagination.html">Pagination Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/parser.html">Template Parser Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/security.html">Security Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/sessions.html">Session Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/table.html">HTML Table Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/trackback.html">Trackback Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/typography.html">Typography Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/unit_testing.html">Unit Testing Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/uri.html">URI Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/user_agent.html">User Agent Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/zip.html">Zip Encoding Class</a></li>
</ul>
</li>
</ul>
<ul class="current">
<li class="toctree-l1 current"><a class="reference internal" href="index.html">Database Reference</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="examples.html">Quick Start: Usage Examples</a></li>
<li class="toctree-l2"><a class="reference internal" href="configuration.html">Database Configuration</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="">Connecting to a Database</a></li>
<li class="toctree-l2"><a class="reference internal" href="queries.html">Running Queries</a></li>
<li class="toctree-l2"><a class="reference internal" href="results.html">Generating Query Results</a></li>
<li class="toctree-l2"><a class="reference internal" href="helpers.html">Query Helper Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="query_builder.html">Query Builder Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="transactions.html">Transactions</a></li>
<li class="toctree-l2"><a class="reference internal" href="metadata.html">Getting MetaData</a></li>
<li class="toctree-l2"><a class="reference internal" href="call_function.html">Custom Function Calls</a></li>
<li class="toctree-l2"><a class="reference internal" href="caching.html">Query Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="forge.html">Database Manipulation with Database Forge</a></li>
<li class="toctree-l2"><a class="reference internal" href="utilities.html">Database Utilities Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="db_driver_reference.html">Database Driver Reference</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
</ul>
</li>
</ul>

      </div>
    
      
  </div>
</div>
<div id="nav2">
  <a href="#" id="openToc">
    <img src="" title="Toggle Table of Contents" alt="Toggle Table of Contents" />
  </a>
</div>

  <div class="wy-grid-for-nav">

    
    <nav data-toggle="wy-nav-shift" class="wy-nav-side">
      <div class="wy-side-nav-search">
        
          <a href="../index.html" class="fa fa-home"> CodeIgniter</a>
        
        
<div role="search">
  <form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
    <input type="text" name="q" placeholder="Search docs" />
    <input type="hidden" name="check_keywords" value="yes" />
    <input type="hidden" name="area" value="default" />
  </form>
</div>
      </div>

      <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
        
          
          
              <ul>
<li class="toctree-l1"><a class="reference internal" href="../general/welcome.html">Welcome to CodeIgniter</a><ul class="simple">
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer&#8217;s Certificate of Origin 1.1</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../general/index.html">General Topics</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../general/urls.html">CodeIgniter URLs</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/controllers.html">Controllers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/reserved_names.html">Reserved Names</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/views.html">Views</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/models.html">Models</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/helpers.html">Helpers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/libraries.html">Using CodeIgniter Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/creating_libraries.html">Creating Libraries</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/drivers.html">Using CodeIgniter Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/creating_drivers.html">Creating Drivers</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/core_classes.html">Creating Core System Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/ancillary_classes.html">Creating Ancillary Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/hooks.html">Hooks - Extending the Framework Core</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/autoloader.html">Auto-loading Resources</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/common_functions.html">Common Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/compatibility_functions.html">Compatibility Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/routing.html">URI Routing</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/errors.html">Error Handling</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/caching.html">Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/profiling.html">Profiling Your Application</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/cli.html">Running via the CLI</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/managing_apps.html">Managing your Applications</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/environments.html">Handling Multiple Environments</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/alternative_php.html">Alternate PHP Syntax for View Files</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/security.html">Security</a></li>
<li class="toctree-l2"><a class="reference internal" href="../general/styleguide.html">PHP Style Guide</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../libraries/index.html">Libraries</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../libraries/benchmark.html">Benchmarking Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/caching.html">Caching Driver</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/calendar.html">Calendaring Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/cart.html">Shopping Cart Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/config.html">Config Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/email.html">Email Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encrypt.html">Encrypt Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/encryption.html">Encryption Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/file_uploading.html">File Uploading Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/form_validation.html">Form Validation</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/ftp.html">FTP Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/image_lib.html">Image Manipulation Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/input.html">Input Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/javascript.html">Javascript Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/language.html">Language Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/loader.html">Loader Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/migration.html">Migrations Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/output.html">Output Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/pagination.html">Pagination Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/parser.html">Template Parser Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/security.html">Security Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/sessions.html">Session Library</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/table.html">HTML Table Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/trackback.html">Trackback Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/typography.html">Typography Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/unit_testing.html">Unit Testing Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/uri.html">URI Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/user_agent.html">User Agent Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
<li class="toctree-l2"><a class="reference internal" href="../libraries/zip.html">Zip Encoding Class</a></li>
</ul>
</li>
</ul>
<ul class="current">
<li class="toctree-l1 current"><a class="reference internal" href="index.html">Database Reference</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="examples.html">Quick Start: Usage Examples</a></li>
<li class="toctree-l2"><a class="reference internal" href="configuration.html">Database Configuration</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="">Connecting to a Database</a></li>
<li class="toctree-l2"><a class="reference internal" href="queries.html">Running Queries</a></li>
<li class="toctree-l2"><a class="reference internal" href="results.html">Generating Query Results</a></li>
<li class="toctree-l2"><a class="reference internal" href="helpers.html">Query Helper Functions</a></li>
<li class="toctree-l2"><a class="reference internal" href="query_builder.html">Query Builder Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="transactions.html">Transactions</a></li>
<li class="toctree-l2"><a class="reference internal" href="metadata.html">Getting MetaData</a></li>
<li class="toctree-l2"><a class="reference internal" href="call_function.html">Custom Function Calls</a></li>
<li class="toctree-l2"><a class="reference internal" href="caching.html">Query Caching</a></li>
<li class="toctree-l2"><a class="reference internal" href="forge.html">Database Manipulation with Database Forge</a></li>
<li class="toctree-l2"><a class="reference internal" href="utilities.html">Database Utilities Class</a></li>
<li class="toctree-l2"><a class="reference internal" href="db_driver_reference.html">Database Driver Reference</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
</ul>
</li>
</ul>

          
        
      </div>
      &nbsp;
    </nav>

    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">

      
      <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
        <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
        <a href="../index.html">CodeIgniter</a>
      </nav>


      
      <div class="wy-nav-content">
        <div class="rst-content">
          <div role="navigation" aria-label="breadcrumbs navigation">
  <ul class="wy-breadcrumbs">
    <li><a href="../index.html">Docs</a> &raquo;</li>
      
        <li><a href="index.html">Database Reference</a> &raquo;</li>
      
    <li>Connecting to your Database</li>
    <li class="wy-breadcrumbs-aside">
      
    </li>
    <div style="float:right;margin-left:5px;" id="closeMe">
      <img title="Classic Layout" alt="classic layout" src="" />
    </div>
  </ul>
  <hr/>
</div>
          <div role="main" class="document">
            
  <div class="section" id="connecting-to-your-database">
<h1>Connecting to your Database<a class="headerlink" href="#connecting-to-your-database" title="Permalink to this headline">¶</a></h1>
<p>There are two ways to connect to a database:</p>
<div class="section" id="automatically-connecting">
<h2>Automatically Connecting<a class="headerlink" href="#automatically-connecting" title="Permalink to this headline">¶</a></h2>
<p>The &#8220;auto connect&#8221; feature will load and instantiate the database class
with every page load. To enable &#8220;auto connecting&#8221;, add the word database
to the library array, as indicated in the following file:</p>
<p>application/config/autoload.php</p>
</div>
<div class="section" id="manually-connecting">
<h2>Manually Connecting<a class="headerlink" href="#manually-connecting" title="Permalink to this headline">¶</a></h2>
<p>If only some of your pages require database connectivity you can
manually connect to your database by adding this line of code in any
function where it is needed, or in your class constructor to make the
database available globally in that class.</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">();</span>
</pre></div>
</div>
<p>If the above function does <strong>not</strong> contain any information in the first
parameter it will connect to the group specified in your database config
file. For most people, this is the preferred method of use.</p>
<div class="section" id="available-parameters">
<h3>Available Parameters<a class="headerlink" href="#available-parameters" title="Permalink to this headline">¶</a></h3>
<ol class="arabic simple">
<li>The database connection values, passed either as an array or a DSN
string.</li>
<li>TRUE/FALSE (boolean). Whether to return the connection ID (see
Connecting to Multiple Databases below).</li>
<li>TRUE/FALSE (boolean). Whether to enable the Query Builder class. Set
to TRUE by default.</li>
</ol>
</div>
<div class="section" id="manually-connecting-to-a-database">
<h3>Manually Connecting to a Database<a class="headerlink" href="#manually-connecting-to-a-database" title="Permalink to this headline">¶</a></h3>
<p>The first parameter of this function can <strong>optionally</strong> be used to
specify a particular database group from your config file, or you can
even submit connection values for a database that is not specified in
your config file. Examples:</p>
<p>To choose a specific group from your config file you can do this:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="s1">&#39;group_name&#39;</span><span class="p">);</span>
</pre></div>
</div>
<p>Where group_name is the name of the connection group from your config
file.</p>
<p>To connect manually to a desired database you can pass an array of
values:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;hostname&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;localhost&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;username&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;myusername&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;password&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;mypassword&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;database&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;mydatabase&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;dbdriver&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;mysqli&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;dbprefix&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;pconnect&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="k">FALSE</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;db_debug&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="k">TRUE</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;cache_on&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="k">FALSE</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;cachedir&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;char_set&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;utf8&#39;</span><span class="p">;</span>
<span class="nv">$config</span><span class="p">[</span><span class="s1">&#39;dbcollat&#39;</span><span class="p">]</span> <span class="o">=</span> <span class="s1">&#39;utf8_general_ci&#39;</span><span class="p">;</span>
<span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="nv">$config</span><span class="p">);</span>
</pre></div>
</div>
<p>For information on each of these values please see the <a class="reference internal" href="configuration.html"><em>configuration
page</em></a>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>For the PDO driver, you should use the $config[&#8216;dsn&#8217;] setting
instead of &#8216;hostname&#8217; and &#8216;database&#8217;:</p>
<div class="last line-block">
<div class="line"><br /></div>
<div class="line">$config[&#8216;dsn&#8217;] = &#8216;mysql:host=localhost;dbname=mydatabase&#8217;;</div>
</div>
</div>
<p>Or you can submit your database values as a Data Source Name. DSNs must
have this prototype:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$dsn</span> <span class="o">=</span> <span class="s1">&#39;dbdriver://username:password@hostname/database&#39;</span><span class="p">;</span>
<span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="nv">$dsn</span><span class="p">);</span>
</pre></div>
</div>
<p>To override default config values when connecting with a DSN string, add
the config variables as a query string.</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$dsn</span> <span class="o">=</span> <span class="s1">&#39;dbdriver://username:password@hostname/database?char_set=utf8&amp;dbcollat=utf8_general_ci&amp;cache_on=true&amp;cachedir=/path/to/cache&#39;</span><span class="p">;</span>
<span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="nv">$dsn</span><span class="p">);</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="connecting-to-multiple-databases">
<h2>Connecting to Multiple Databases<a class="headerlink" href="#connecting-to-multiple-databases" title="Permalink to this headline">¶</a></h2>
<p>If you need to connect to more than one database simultaneously you can
do so as follows:</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$DB1</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="s1">&#39;group_one&#39;</span><span class="p">,</span> <span class="k">TRUE</span><span class="p">);</span>
<span class="nv">$DB2</span> <span class="o">=</span> <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">database</span><span class="p">(</span><span class="s1">&#39;group_two&#39;</span><span class="p">,</span> <span class="k">TRUE</span><span class="p">);</span>
</pre></div>
</div>
<p>Note: Change the words &#8220;group_one&#8221; and &#8220;group_two&#8221; to the specific
group names you are connecting to (or you can pass the connection values
as indicated above).</p>
<p>By setting the second parameter to TRUE (boolean) the function will
return the database object.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>When you connect this way, you will use your object name to issue
commands rather than the syntax used throughout this guide. In other
words, rather than issuing commands with:</p>
<div class="last line-block">
<div class="line"><br /></div>
<div class="line">$this-&gt;db-&gt;query();</div>
<div class="line">$this-&gt;db-&gt;result();</div>
<div class="line">etc...</div>
<div class="line"><br /></div>
<div class="line">You will instead use:</div>
<div class="line"><br /></div>
<div class="line">$DB1-&gt;query();</div>
<div class="line">$DB1-&gt;result();</div>
<div class="line">etc...</div>
</div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>You don&#8217;t need to create separate database configurations if you
only need to use a different database on the same connection. You
can switch to a different database when you need to, like this:</p>
<div class="last line-block">
<div class="line">$this-&gt;db-&gt;db_select($database2_name);</div>
</div>
</div>
</div>
<div class="section" id="reconnecting-keeping-the-connection-alive">
<h2>Reconnecting / Keeping the Connection Alive<a class="headerlink" href="#reconnecting-keeping-the-connection-alive" title="Permalink to this headline">¶</a></h2>
<p>If the database server&#8217;s idle timeout is exceeded while you&#8217;re doing
some heavy PHP lifting (processing an image, for instance), you should
consider pinging the server by using the reconnect() method before
sending further queries, which can gracefully keep the connection alive
or re-establish it.</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">db</span><span class="o">-&gt;</span><span class="na">reconnect</span><span class="p">();</span>
</pre></div>
</div>
</div>
<div class="section" id="manually-closing-the-connection">
<h2>Manually closing the Connection<a class="headerlink" href="#manually-closing-the-connection" title="Permalink to this headline">¶</a></h2>
<p>While CodeIgniter intelligently takes care of closing your database
connections, you can explicitly close the connection.</p>
<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">db</span><span class="o">-&gt;</span><span class="na">close</span><span class="p">();</span>
</pre></div>
</div>
</div>
</div>


          </div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="queries.html" class="btn btn-neutral float-right" title="Queries">Next <span class="fa fa-arrow-circle-right"></span></a>
      
      
        <a href="configuration.html" class="btn btn-neutral" title="Database Configuration"><span class="fa fa-arrow-circle-left"></span> Previous</a>
      
    </div>
  

  <hr/>

  <div role="contentinfo">
    <p>
        &copy; Copyright 2014 - 2017, British Columbia Institute of Technology.
      Last updated on Jun 19, 2017.
    </p>
  </div>

  Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
  
</footer>
        </div>
      </div>

    </section>

  </div>
  


  

    <script type="text/javascript">
        var DOCUMENTATION_OPTIONS = {
            URL_ROOT:'../',
            VERSION:'3.1.5',
            COLLAPSE_INDEX:false,
            FILE_SUFFIX:'.html',
            HAS_SOURCE:  false
        };
    </script>
      <script type="text/javascript" src="../_static/jquery.js"></script>
      <script type="text/javascript" src="../_static/underscore.js"></script>
      <script type="text/javascript" src="../_static/doctools.js"></script>

  

  
  
    <script type="text/javascript" src="../_static/js/theme.js"></script>
  

  
  
  <script type="text/javascript">
      jQuery(function () {
          SphinxRtdTheme.StickyNav.enable();
      });
  </script>
   

</body>
</html>